Keystone will “contribute dramatically” to global warming and pose an “unacceptable risk to water,” according to a letter posted on the website of environmental group 350.org that visitors could electronically sign and submit to the State Department, which is reviewing the comments. Keep reading.

The Calgary-based pipeline and power giant on Friday pushed the potential in-service date for the Alberta-to-Texas pipeline to the second half of 2015 at the earliest. That’s back from previous in-service estimates of late 2014 or early 2015. Costs for the pipeline’s northern leg, which would link Alberta’s oil sands to the U.S. Midwest and, ultimately, to refineries in Texas, could exceed $5.4-billion because of the delay, CEO Russ Girling said.

“We’re maintaining pipe in the field. We’re maintaining pumps in the field. We’re continuing to acquire right-of-way. We’ve had a rerouting of the pipeline. All of those things cost money,” he said, declining to provide specific numbers.

The company has invested $1.8-billion in the project to date.

Oil sands producers, as well as the Alberta and federal governments, are counting on Keystone XL to help relieve a backlog of bitumen production that has weighed on prices and cut into provincial and federal revenues.

The U.S. State Department is expected to issue a verdict on the much-delayed pipeline this year. U.S. officials are currently reviewing comments received on a draft supplemental environmental impact statement and will release a final version ahead of a 90-day window during which the project’s fate will be decided, TransCanada said in a release.

TransCanada on Friday underlined the project’s scale. Upon completion, the entire Keystone system, including the original pipeline, would carry up to 1.4 million barrels of oil a day – about 40% of total Canadian production and equivalent to 10% of U.S. oil demand, Mr. Girling said in prepared remarks.

The total, including up to 250,000 barrels of Bakken crude, would replace dwindling U.S. imports from Mexico and Venezuela, TransCanada officials have said.

Backers say the project would create jobs and bolster North American energy security. Critics have painted the pipeline as a carbon “bomb” that would exacerbate the impacts of climate change.

A recent analysis by Oil Change International and 350.org said Keystone XL would increase greenhouse gas emissions by the equivalent of 46 coal-fired power plants or 34 million vehicles.

Mr. Girling, who spoke following TransCanada’s annual general meeting in Calgary, brushed off such analyses as “ridiculous nonsense” and part of “barrage of misinformation.

“I believe that those who are fundamentally opposed to our pipeline are getting louder and more shrill as we move towards a decision,” the executive told reporters.

He said shippers remain committed to the project, notwithstanding the delays. Many have turned to rail as soaring production in North Dakota’s Bakken and continued bitumen production backs up along existing export routes.

Imperial Oil Ltd., whose Kearl oil sands mine won’t begin sales of 110,000-barrels-per-day of bitumen before the third-quarter this year, is also eyeing “contingencies” in the event that pipeline projects are delayed, chief executive officer and chairman Rich Kruger said this week.

Those could include rail shipments or potentially scaling back plans to double production by the end of this decade. “We’ll sync up our export capacity with our growth plans,” Mr. Kruger said. Kearl is “not reliant on any one pipeline,” he added.

TransCanada on Friday sketched out plans to advance a $25-billion portfolio of projects. The total includes the $2.3-billion southern segment of Keystone XL, which TransCanada said is now 70% complete.

The company has also set out $9-billion worth of investments tied to liquefied natural gas exports on Canada’s West Coast, as well as a plan to pipe Alberta oil as far east as Saint John, N.B. using portions of its under-used natural gas mainline. Mr. Girling said that plan, dubbed Energy East, could cost north of $6-billion.

TransCanada said Friday it earned $446-million, or 63¢ per share, in the first three months of 2013, up from 50¢ per share or $352 million a year ago. Revenue was $2.25-billion, up from $1.9-billion in the first quarter of 2012.